def sequence_search(alist, v):
    for i in range(len(alist)):  # i指列表的索引下标
        if alist[i] == v:
            return i
    # 没有找到
    return -1


if __name__ == '__main__':
    alist = [4, 3, 5, 1, 233, 66, 99]
    index = sequence_search(alist, 199)
    if index != -1:
        print('找到了，索引值为：', index)
    else:
        print('没有找到')
